As therapeutics for arthropathy such as arthritis and articular rheumatism, steroid agents, nonsteroidal antiphlogistics, antirheumatics, articular function improvers and the like are available these days. They are generally used in unit dosage forms such as capsules, tablets, powders or injections.
Since these capsules, tablets and powders are orally administered, substantial time is however required until the drug reaches a joint area. Moreover, the drug is allowed to migrate only in a small amount to the joint area so that a large dose is needed to exhibit the efficacy of the drug. Problems of general side effects have therefore been indicated. An injection, on the other hand, is applied directly to a joint area, thereby making it possible to increase the concentration of the drug at the joint area. Nonetheless, the drug so injected is generally quickly eliminated from the joint area, so that no drug efficacy can be expected to remain over a long term (for example, from one day to several months or so). If injection is made more frequently to maintain the efficacy of the drug, substantial burden, discomfort or pain is experienced by the patient. Such frequent injection is hence not preferred.
With the foregoing in view, the present invention has as an object the provision of a dosage-form preparation for the treatment of arthropathy, which, when applied directly to a joint area, can achieve a high drug concentration at the target area, can inhibit occurrence of general side effects, can maintain drug efficacy over a long term, and can alleviate the burden on the patient.